"""
Alembic Configuration
数据库迁移配置
"""

from logging.config import fileConfig
from sqlalchemy import engine_from_config
from sqlalchemy import pool
from alembic import context
import os
import sys
from pathlib import Path

# 添加src到Python路径
sys.path.append(str(Path(__file__).parent.parent / "src"))

# 导入数据库模型
from media_create.core.database import Base
from media_create.core.config import settings

# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config

# Interpret the config file for Python logging.
# This line sets up loggers basically.
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# add your model's MetaData object here
# for 'autogenerate' support
target_metadata = Base.metadata

# other values from the config, defined by the needs of env.py,
# can be acquired:
# my_important_option = config.get_main_option("my_important_option")
# ... etc.

def get_database_url():
    """获取数据库连接URL"""
    # 从环境变量获取URL，如果不存在则使用配置文件中的URL
    database_url = os.getenv("DATABASE_URL", settings.database.url)
    return database_url

def run_migrations_offline() -> None:
    """Run migrations in 'offline' mode.

    This configures the context with just a URL
    and not an Engine, though an Engine is acceptable
    here as well.  By skipping the Engine creation
    we don't even need a DBAPI to be available.

    Calls to context.execute() here emit the given string to the
    script output.

    """
    url = get_database_url()
    # 对于离线模式，使用同步URL
    if url.startswith("postgresql+asyncpg://"):
        url = url.replace("postgresql+asyncpg://", "postgresql://")
    
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )

    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    """Run migrations in 'online' mode.

    In this scenario we need to create an Engine
    and associate a connection with the context.

    """
    # 获取数据库URL并转换为同步版本
    database_url = get_database_url()
    sync_database_url = database_url
    if sync_database_url.startswith("postgresql+asyncpg://"):
        sync_database_url = sync_database_url.replace("postgresql+asyncpg://", "postgresql://")
    
    configuration = config.get_section(config.config_ini_section)
    configuration["sqlalchemy.url"] = sync_database_url
    
    connectable = engine_from_config(
        configuration,
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    with connectable.connect() as connection:
        context.configure(
            connection=connection, target_metadata=target_metadata
        )

        with context.begin_transaction():
            context.run_migrations()


if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()